This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. While most peripheral nerves have a remarkable ability to repair themselves after injury, the central nervous system does not spontaneously regenerate. The retrograde transport of injury signals is one of the essential components that allow peripheral neurons to regenerate. Yet, the mechanisms regulating their transport are poorly understood. Our goal is to elucidate the molecular mechanisms by which injury signals are conveyed to the cell body to initiate the cascade of events leading to regeneration. Our previous studies implicate the protein "Sunday Driver" (syd) in transmitting information about injury from the axon back to the neuronal cell body. A better understanding of how nerve injury regulates syd association with the molecular motors and syd recruitment to axonal vesicles may define the mechanisms by which neurons initiate the appropriate regenerative response. We will use proteomics to reveal syd phosphorylation pattern and binding partners prior and following sciatic nerve injury. Syd will be immunoprecipitated from injured or non-injured rat sciatic nerves;the immunoprecipitated material will be separated by SDS-PAGE and sypro-stained bands of interest will be cut and analyzed by mass spectrometry. This proposed collaboration with the UCSF Mass Spectrometry Facility will help understand the role of syd in nerve regeneration and define the molecular mechanisms regulating anterograde and retrograde axonal transport in the context of nerve injury. Our studies may guide the development of new strategies to enhance nerve regeneration following injury.